ACS Applied Energy Materials最新文献

Selenium-based cathodes represent an attractive alternative to sulfur for high-energy-density lithium batteries owing to their high intrinsic electrical conductivity, superior active material utilization, and enhanced volumetric capacity. Unlike sulfur, selenium cathodes in carbonate electrolytes undergo a direct solid–solid conversion with negligible polyselenide dissolution, offering an intrinsic pathway to suppress the shuttle effect. However, the sluggish kinetics and high energy barriers associated with this conversion necessitate the rational design of catalytic reaction interfaces. Here, we demonstrate a metal-organic framework-derived manganese single-atom catalyst anchored to nitrogen-doped carbon (Mn-NC) that fundamentally regulates the selenium conversion pathway in Li–Se batteries. The Mn-NC host, synthesized via Mn²⁺ incorporation into ZIF-8, features a hierarchical bimodal pore architecture and atomically dispersed Mn active sites stabilized within a defect-rich nitrogen–carbon matrix. These structural attributes synergistically enable uniform selenium confinement, improved Se-host adherence, and accelerated Se redox kinetics, offering discharge capacities of 508 and 333 mAh g^–1 at 0.1 and 5 C, respectively. Density functional theory (DFT) analyses substantiate that Mn–N₄ centers significantly lower the energy barriers for Se₈ ↔ Li₂Se conversion, induce strong chemisorptive interactions with Se, and promote fast, reversible solid-state redox processes. The present work establishes a general strategy for engineering solid–solid chalcogen conversion pathways using atomically precise active centers. Furthermore, the in situ incorporation of earth-abundant Mn single atoms into a template-free hierarchical carbon host provides a potentially scalable route toward advanced chalcogen-based energy storage systems.

In the present study, we have modified multi-walled carbon nanotube (MWCNT) fibers using a high-power visible laser beam (∼532 nm) with a pulse energy density of ∼0.48 mJ/cm² under ambient conditions. The laser-irradiated fibers exhibited significant improvement in electrical conductivity with a minimal impact on the Seebeck coefficient. The optimally irradiated fibers (50 s exposure time) showed the highest power factor of ∼65 μW/mK² near room temperature, representing an enhancement of nearly 56% compared to pristine fibers. Detailed characterization revealed that the rapid temperature rise of samples on laser exposure leads to defect annihilation, removal of amorphous carbon, and improved alignment of MWCNTs within the fiber. These modifications collectively contribute to the improvement in the thermoelectric performance and fracture strength of laser-irradiated samples. The present scalable approach of improving the thermoelectric and mechanical properties of MWCNT fibers through laser beam exposure holds great promise for wearable thermoelectric applications.

Aqueous zinc–ion batteries are promising for safe and low-cost energy storage, but Zn metal anodes still suffer from dendritic deposition, corrosion, hydrogen evolution, and insulating by-products. Conventional protective layers can block water contact or tune surface wettability, but many static coatings gradually lose regulatory capability as the Zn/electrolyte interface evolves during repeated plating/stripping. Herein, a SnO/PVDF composite coating prepared by a doctor-blade method is developed to induce interfacial reconstruction on Zn. PVDF maintains coating continuity, while SnO provides polar Sn–O sites and, more importantly, undergoes cycling-induced chemical evolution to generate cooperative Sn and oxidized Sn–O environments (SnO and SnO₂). During Zn plating/stripping, the coating evolves into a mixed Sn/SnO/SnO₂-containing interphase that promotes uniform Zn nucleation, moderates local electric-field and ion-flux heterogeneity, and suppresses water-induced side reactions. Consequently, the optimized 60% SnO/PVDF-coated Zn anode shows a reduced nucleation overpotential of 16.6 mV, delivers stable Zn plating/stripping for over 2000 h under 1 mA cm⁻², and over 1000 h under 5 mA cm⁻². Furthermore, the full cell paired with an NH₄V₄O₁₀ cathode achieves stable cycling for over 2000 cycles. This work highlights interfacial reconstruction induced by cycling as an effective strategy for stabilizing aqueous Zn metal anodes.

The thermoelectric performance of n-type Mg₃(Sb_1–xBi_x)₂ is limited by its moderate carrier mobility. However, a detailed study on the dominant scattering mechanism in this material system has not been reported. In this work, using a modified single parabolic band (SPB) model, the relevant scattering information has been obtained for Mg₃(Sb_1–xBi_x)₂ with x = 0.25–0.65. Our results indicate the prevalence of polar optical phonon (POP) scattering in the entire compositional range, with the other major contributor being alloy scattering or acoustic phonon scattering, depending on the bismuth content. Given the dominance of polar optical phonon scattering, its suppression has been identified as a possible route toward improving the thermoelectric properties. Predictions of the thermoelectric power factor indicate a doubling of the values in the absence of POP scattering. The work also reveals the suitability of the modified SPB technique for studying the compositional trends of scattering parameters in solid solutions and for also identifying fundamental physical effects (such as band convergence).

All-solid-state batteries (ASSBs) have enhanced safety features and potential for high energy density. However, their path to commercialization has obstacles because of the inadequate solid–solid contact and mismatched ionic and electronic transport properties in composite cathodes. In this study, we investigate the effect of Li₆PS₅Cl (LPSC) solid-state electrolyte particle size and CAM/SSE ratio (using high-Ni NCM90) on interfacial transport kinetics and coupled electrochemical–mechanical stability. Three-dimensional simulations with LAMMPS and multiscale characterization methods reveal a trade-off between ionic and electronic pathways: refined LPSC refined enhances void filling, reduces Li-ion tortuosity, and improves ionic continuity, but also increases the tortuosity of electronic pathways. A volume ratio of 50:50 between CAM and SSE results in a balance between ionic continuity and electronic percolation, stabilizes the growth of CEI, and maintains 65.8% of the capacity after 2C cycling when returning to a low rate. Insufficient cathode electrolyte interphase (CEI) results in interfacial contact degradation, uneven CEI layer formation, and impedance hotspots over extended periods, as well as microcracking and accelerated capacity loss. These findings provide design guidelines for stable, high-performance sulfide composite cathodes.

Considering the distinct charge storage mechanisms, it is difficult to achieve high energy density while maintaining high power density in electric double-layer capacitors (EDLCs) and pseudocapacitors. Therefore, it is necessary to rationally design the structure of electrode materials to balance these properties. In this work, a positive electrode material is designed based on reduced graphene oxide-coated NiCo layered double hydroxide (NiCo-LDH@rGO), which exhibits high specific capacity (218.64 mAh g⁻¹) and favorable rate capability. Notably, this work features the rational design of both electrodes: the rGO coating on NiCo-LDH enhances interfacial conductivity and structural stability, while the negative electrode is constructed as a CNT/rGO hybrid carbon hydrogel, where one-dimensional CNTs serve as both physical spacers to prevent rGO restacking and conductive bridges to construct a three-dimensional hierarchical conductive network. Consequently, the negative electrode material demonstrates exceptional cycling stability. The asymmetric supercapacitor assembled using NiCo-LDH@rGO and 5CNTs@rGO achieved an energy density of 56.30 Wh kg⁻¹ at a power density of 108.26 W kg⁻¹.

Developing donor polymers compatible with scalable and eco-friendly manufacturing remains a critical challenge for the lab-to-fab transition of organic photovoltaics (OPVs). Here, we report a series of D18-based terpolymers incorporating controlled amounts of thiophene or hexylthiophene comonomers to systematically expand the processing window while preserving the optoelectronic characteristics of the parent polymer. Compared to pristine D18, thiophene-engineered terpolymers (P5T and P15T) exhibit enhanced solubility, improved film uniformity, and superior device reproducibility under ambient blade-coating conditions. Notably, P15T uniquely enables the fabrication of uniform active layers from o-xylene, a green solvent generally incompatible with D18-based systems. Although the resulting devices exhibit a moderate decrease in PCE relative to chloroform-processed counterparts, this capability substantially broadens the processing window and represents an important step toward more sustainable organic photovoltaic manufacturing. Devices fabricated under an ambient atmosphere with a large active areas (0.55 cm²) achieve power conversion efficiencies up to 8.66%, demonstrating competitive performance under industrially relevant constraints. In contrast, hexylthiophene-rich analogues show reduced molecular weight, poor film formation, and limited photovoltaic performance, highlighting the narrow design window between solubility enhancement and electronic disruption. Overall, this work demonstrates that subtle backbone engineering enables decoupling of solubility and electronic properties in high-performance donor polymers. These findings establish practical molecular design guidelines for scalable, green-solvent-processed OPVs and contribute to bridging the gap between laboratory-scale efficiency and industrial manufacturing.

The high theoretical capacity of cobalt sulfide makes it a compelling cathode material for aqueous alkaline zinc batteries (AAZBs). Nevertheless, they still fall short of the performance requirements for practical AAZBs due to the unfavorable OH^– adsorption capability and low electrical conductivity, which originate from an intrinsically unfavorable d-orbital configuration of Co centers. Herein, we propose a strategy to precisely modulate the d-orbital configuration of Co centers via spontaneous interfacial electron transfer from a Ti₃C₂T_x MXene substrate into a mixed-phase CoS/Co₉S₈ (CS@MXene). This electronic perturbation shifts the Co d-band center upward and improves the metallic character, thus strengthening its OH^– binding affinity, enhancing electrical conductivity, and accelerating the redox kinetics. Consequently, the battery assembled with the CS@MXene cathode delivers a high areal capacity of 1.69 mAh cm^–2 and superior rate capability. It also exhibits outstanding cycling performance with only 0.0065% of capacity fading after 1700 cycles and an average coulombic efficiency of ~97%. Moreover, the CS@MXene//Zn battery achieves a peak energy density of 2.95 mWh cm^–2 with a peak power density of 17.5 mW cm^–2. This work offers a valuable perspective on designing advanced electrodes via electronic structure modulation for energy storage devices.

With the continuous development of society and the improvement of living standards, the need for renewable resources has become increasingly urgent. In the field of electrochemical energy storage systems, supercapacitors garner significant attention due to their rapid charging and discharging capabilities, high power density, and environmentally friendly nature. However, the effectiveness of electrocatalytic reactions largely depends on the kinetics of the hydrogen evolution reaction and oxygen evolution reaction (OER). This study explores the impact of Li⁺ doping on the electrochemical properties of Co₉S₈/Ni₉S₈ materials. Li-Co₉S₈/Ni₉S₈ is successfully synthesized via a two-step hydrothermal method, and the Li-Co₉S₈/Ni₉S₈-0.3 material demonstrates a mass specific capacitance of 855 F g⁻¹ at a current density of 0.5 A g⁻¹. The assembled asymmetric supercapacitor achieves a power density of 4050 W kg⁻¹ at an energy density of 86.7 Wh kg⁻¹. In a 1.0 M KOH electrolyte, the Li-Co₉S₈/Ni₉S₈-0.3 material exhibits efficient OER performance, with an overpotential of 191.4 mV at a current density of 20 mA cm⁻². Moreover, the material exhibits a low battery voltage of 1.50 V at 20 mA cm⁻² and maintains excellent stability over 30 h of cycling.

Increasing the energy density of lithium-ion batteries is a central challenge for next-generation electrified technologies. Silicon (Si) is a premier anode candidate due to its high theoretical capacity; yet, its practical use is hindered by extreme volume expansion and subsequent mechanical failure. To address these chronic issues, we demonstrate a comprehensive electrode-electrolyte engineering strategy by synergistically pairing a hierarchical secondary Si/C microrod (μ-rod) architecture with a customized ether-based electrolyte. This approach targets to bridge the gap between nanoscale reaction kinetics and microscale electrode stability without relying on complex, nonscalable particle synthesis. Multiscale structural characterizations confirmed the robust, anisotropic geometry of the secondary micrometer-sized rods consisting of the nanocrystalline Si primary particles. Electrochemical evaluations demonstrate that the integrated μ-rod architecture exhibits superior electromechanical stability when paired with the fluorinated ether electrolyte, outperforming conventional carbonate systems. Consequently, the Li||Si half-cell achieved 76.4% capacity retention after 300 cycles, while practical validation in a Si||NMC622 full cell revealed 71.4% capacity after 100 cycles. Operando strain measurements demonstrate mechanically resilient response of the μ-rod architecture in fluorinated ether electrolyte. These results highlight the synergy between a commercially viable mesoscale structured electrode and a compatible electrolyte in enabling structurally durable and electrochemically stable Si-based anodes.